Conventionally, wiring boards for mounting an electronic part are constituted by an insulating base formed of an electrically insulating material, and a wiring conductor provided in the insulating base.
Examples of this kind of wiring board include a wiring board comprising an insulating base having a side surface including a recessed portion, wiring conductors provided on an upper surface of the insulating base, a lower surface of the insulating base, and in the recessed portion, and through conductors connected to the wiring conductor provided on the upper surface and the wiring conductor provided on the lower surface, the through conductors being provided in the insulating base (e.g., see Patent Literature 1).